Environmental exposure to non-essential trace elements in two bat species from urbanised (Tadarida teniotis) and open land (Miniopterus schreibersii) areas in Italy

Trace metal accumulation with age in bats: a case study on Pipistrellus kuhlii lepidus from a relatively unpolluted area

Bats, as exceptionally long-lived small mammals, are at particular risk of metal poisoning due to the tendency of metals to bioaccumulate throughout their lives. In our study, we investigated the general question of how trace metal concentrations change with age in different bat tissues on the example of Pipistrellus kuhlii lepidus, which lives for years in one area and is strongly associated with urban environments. To determine the exact age of the individuals, osteochronology was applied, counting the number of dentine rings in cross-sections of the upper canine tooth of each individual. The age of 57 individuals of P. kuhlii lepidus, representing ca. 10% of the colony, was identified. Whole internal organs (liver, kidneys, lungs, and forearm bones) and samples of external tissues (fur and wing membrane) were analyzed for concentrations of Cd, Cu, Pb, and Zn using atomic absorption spectrometry. We found that concentrations of Cd, Pb, and Zn, but not Cu, increase with the age of the bats, but in relatively unpolluted areas, metal concentrations do not reach the level which can cause chronic adverse effects. Nevertheless, due to the confirmed accumulation of metals in bat tissues with age, toxic effects can be expected in older individuals in areas where trace metal concentrations are elevated.

Landscape degradation drives metal bioaccumulation in bats from Atlantic Forest cacao region, Brazil

Agricultural landscapes worldwide are heavily sprayed with agrochemicals to increase crop productivity. These agrochemicals release bio-accumulative pollutants such as heavy metals that often persist in the environment with harmful impacts on biota. In a prime endangered Atlantic Forest biome, in Bahia, Brazil, agroforestry of cacao (Theobroma cacao) provides a livelihood for small farmers and suitable habitats for forest species. However, landscape transformation to pasture and monoculture expose vulnerable communities to scarcely evaluated pollutants with unknown effects on the health of humans and animals. We assessed the bioaccumulation of manganese (Mn), lead (Pb), and copper (Cu) by analyzing hair samples of 326 bats representing 28 species across 15 cacao agroforestry and 2 forest remnants. Bats from regions heavily disturbed by pastures and monocultures showed higher levels of Pb (41.20 µg/g) and Mn (0.44 µg/g) compared to those from areas where forest or cacao agroforestry dominates the landscape. Local grassland covers increased Pb bioaccumulation, while forest cover reduced it. Cacao agroforestry appeared to increase Cu exposure, likely due to fungicide use. This study pioneers the evaluation of heavy metal accumulation in bats inhabiting cacao agroforestry and Atlantic Forest remnants, highlighting the need for sustainable agricultural practices to protect wildlife and ecosystem health.

Past anthropogenic impacts revealed by trace elements in cave guano

Natural and human-induced toxic elements can accumulate in the environment, posing significant risks to human health and ecosystems. This study explores cave bat guano, an unconventional and relatively under-researched environmental repository, to reveal historical pollution trends and sources. Through trace elements analysis of a 1.5-m-thick guano deposit from Zidită Cave (Romania), we track changes in mining and metallurgy from 1000 CE-2012. We identified substantial pollution primarily from porphyry copper and Au-Ag-Te mines, but also impacts from usage of leaded gasoline and agricultural practices. Our record shows disruptions caused by the Bubonic plague around 1250 CE and a major surge ∼ 1500 CE. After the decline triggered by the European silver market collapse in 1525 CE, our study reveals a brief mining revival. This resurgence was followed by a continuous decline lasting until the early 1800s, driven by socio-economic upheavals and recurrent outbreaks of the bubonic plagues. The Industrial Revolution sparked prolonged growth that lasted until 1989 CE, only briefly interrupted by the Great Depression and World War II. Consequently, cave bat guano proves to be a critical resource for understanding spatial pollution patterns, both locally and regionally, and for identifying specific pollution sources.

A systematic review of trace elements in the tissues of bats (Chiroptera)

Bats constitute about 22% of known mammal species; they have various ecological roles and provide many ecosystem services. Bats suffer from several threats caused by anthropization, including exposure to toxic metals and metalloids. We analyzed 75 papers in a systematic literature review to investigate how species, diet, and tissue type impact bioaccumulation. Most studies documented element accumulation in fur, liver, and kidney; at least 36 metals and metalloids have been measured in bat tissues, among the most studied were mercury and zinc. Comparisons with known toxicological thresholds for other mammals showed concerning values for mercury and zinc in bat hair, lead and some essential metals in liver, and iron and calcium in kidneys. Moreover, accumulation patterns in tissues differed depending on bat diet: insectivorous bats showed higher metal concentrations in fur than in liver and kidney while frugivorous species showed higher values in liver and kidney than in fur. Finally, among the bat species that have been studied in more than two papers, the big brown bat (Eptesicus fuscus) show values of mercury in hair and copper in liver that exceed the known thresholds; as does copper in the liver of the little brown bat (Myotis lucifugus). Most studies have been conducted in temperate North America and Eurasia, areas with the lowest bat species diversity; there is a paucity of data on tropical bat species. This review points out several information gaps in the understanding of metal contamination in bats, including a lack of measured toxicity thresholds specific for bat tissues. Data on trace element bioaccumulation and its associated health effects on bats is important for conservation of bat species, many of which are threatened.

Genotoxic, mutagenic, and cytotoxic analysis in bats in mining area

Pollution generated by the mining industry can cause harm to wildlife. This study aimed to evaluate the cytotoxicity, genotoxicity and mutagenicity in bats environmentally exposed to open pit mining. Thus, 62 bats of the following species, Carollia perspicillata, Glossophaga soricina, Phyllostomus hastatus, and Desmodus rotundus exposed to mining activities (ferronickel) were used in the analysis. The animals were obtained in samplings in July and November of 2021, totaling 8 days of sampling in the field. The results indicated that species differ in the frequency of genotoxic damage between sampling points within the mining landscape. Cytotoxicity was observed by scoring of karyorrhexis, pyknosis and karyolysis. The most captured species, C. perspicillata, showed differences in DNA damage between exposed and unexposed populations, but no differences were observed between males (n = 14) and females (n = 20). G. soricina was also a sensitive species for indicating a high frequency of DNA damages compared to the omnivore P. hastatus. Elements such as Mn, Cr, Pb, and Zn observed in water samples were at high levels in the mining area. We conclude that bats in mining areas are susceptible to increased DNA damage as already identified for other species.

Toxic elements in arctic and sub-arctic brown bears: Blood concentrations of As, Cd, Hg and Pb in relation to diet, age, and human footprint

Contamination with arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb) is a global concern impairing resilience of organisms and ecosystems. Proximity to emission sources increases exposure risk but remoteness does not alleviate it. These toxic elements are transported in atmospheric and oceanic pathways and accumulate in organisms. Mercury accumulates in higher trophic levels. Brown bears (Ursus arctos), which often live in remote areas, are long-lived omnivores, feeding on salmon (Oncorhynchus spp.) and berries (Vaccinium spp.), resources also consumed by humans. We measured blood concentrations of As, Cd, Hg and Pb in bears (n = 72) four years and older in Scandinavia and three national parks in Alaska, USA (Lake Clark, Katmai and Gates of the Arctic) using high-resolution, inductively-coupled plasma sector field mass spectrometry. Age and sex of the bears, as well as the typical population level diet was associated with blood element concentrations using generalized linear regression models. Alaskan bears consuming salmon had higher Hg blood concentrations compared to Scandinavian bears feeding on berries, ants (Formica spp.) and moose (Alces). Cadmium and Pb blood concentrations were higher in Scandinavian bears than in Alaskan bears. Bears using marine food sources, in addition to salmon in Katmai, had higher As blood concentrations than bears in Scandinavia. Blood concentrations of Cd and Pb, as well as for As in female bears increased with age. Arsenic in males and Hg concentrations decreased with age. We detected elevated levels of toxic elements in bears from landscapes that are among the most pristine on the planet. Sources are unknown but anthropogenic emissions are most likely involved. All study areas face upcoming change: Increasing tourism and mining in Alaska and more intensive forestry in Scandinavia, combined with global climate change in both regions. Baseline contaminant concentrations as presented here are important knowledge in our changing world.

Admittance to Wildlife Rehabilitation Centres Points to Adverse Effects of Climate Change on Insectivorous Bats

Climate change is exerting a broad range of (mostly adverse) effects on biodiversity, and more are expected under future scenarios. Impacts on species that deliver key ecosystem services, such as bats, are especially concerning, so their better understanding is key to preventing or mitigating them. Due to their physiological requirements, bats are especially sensitive to environmental temperatures and water availability, and heatwave-related mortality has been reported for flying foxes and, more anecdotally, other bat species. For temperate regions, to date, no study has highlighted an association between temperature extremes and bat mortality, mostly due to the difficulty of relying on data series covering long timespans. Heatwaves may affect bats, causing thermal shock and acute dehydration so bats can fall from the roost and, in some cases, are rescued by the public and brought to wildlife rehabilitation centres (WRCs). In our work, we considered a dataset spanning over 20 years of bat admittance to Italian WRCs, covering 5842 bats, and hypothesised that in summer, the number of admitted bats will increase in hotter weeks and young bats will be more exposed to heat stress than adults. We confirmed our first hypothesis for both the overall sample and three out of five synurbic species for which data were available, whereas hot weeks affected both young and adults, pointing to an especially concerning effect on bat survival and reproduction. Although our study is correlative, the existence of a causative relationship between high temperatures and grounded bats is still the best explanation for the recorded patterns. We urge such a relationship to be explored via extensive monitoring of urban bat roosts to inform appropriate management of bat communities in such environments and preserve the precious ecosystem services such mammals provide, especially insectivory services.

Urban tolerance is phylogenetically constrained and mediated by pre-adaptations in African bats

With increasing urbanization, particularly in developing countries, it is important to understand how local biota will respond to such landscape changes. Bats comprise one of the most diverse groups of mammals in urban areas, and many species are threatened by habitat destruction and land use change. Yet, in Africa, the response of bats to urban areas is relatively understudied. Therefore, we collated data on urban presence, phylogenetic relationship, and ecological traits of 54 insectivorous bats in Africa from available literature to test if their response to urbanization was phylogenetically and/or ecologically driven. Ancestral state reconstruction of urban tolerance, defined by functional group and presence observed in urban areas, suggests that ancestral African bat species could adapt to urban landscapes, and significant phylogenetic signal for urban tolerance indicates that this ability is evolutionarily conserved and mediated by pre-adaptations. Specifically, traits of high wing loading and aspect ratio, and flexible roosting strategies, enable occupancy of urban areas. Therefore, our results identify the traits that predict which bat species will likely occur in urban areas, and which vulnerable bat clades conservation efforts should focus on to reduce loss of both functional and phylogenetic diversity in Africa. We, additionally, highlight several gaps in research that should be investigated in future studies to provide better monitoring of the impact urbanization will have on African bats.

Iron Content, Iron Speciation and Phycocyanin in Commercial Samples of Arthrospira spp

Cyanobacteria are characterized by high iron content. In this research, we collected ten commercial samples of Arthrospira spp. sold as food supplement to determine iron content and assess whether iron speciation showed variability among samples and changed respect to A. platensis grown in controlled conditions. Particular attention was also paid to phycocyanin, as an iron-binding protein. In six of the ten samples, 14 essential and non-essential trace elements were analysed using ICP-MS. Iron content measured in samples using atomic absorption spectrometry (AAS) varied from 353 (sample S5) to 1459 (sample S7) µg g^-1 dry weight and was in the range of those reported by other authors in commercial supplements. Iron speciation was studied using size exclusion chromatography followed by the analysis of the collected fraction for the determination of iron by AAS and for protein separation using SDS-PAGE. Overlapping chromatographic profiles were obtained for total proteins, phycocyanin and iron, although quantitative differences were evidenced among the samples analysed. In most samples, iron was mainly bound to ligands with high molecular mass; however, in four samples iron was also bound to ligands with low molecular mass. In fractions containing the most relevant iron burden, the principal protein was phycocyanin, confirming its role as an iron-binding protein in commercial samples.

Conversion of Plastic Waste to Carbon-Based Compounds and Application in Energy Storage Devices

At present, plastic waste accumulation has been observed as one of the most alarming environmental challenges, affecting all forms of life, economy, and natural ecosystems, worldwide. The overproduction of plastic materials is mainly due to human population explosion as well as extraordinary proliferation in the global economy accompanied by global productivity. Under this threat, the development of benign and green alternative solutions instead of traditional disposal methods such as conversion of plastic waste materials into cherished carbonaceous nanomaterials such as carbon nanotubes (CNTs), carbon quantum dots (CQDs), graphene, activated carbon, and porous carbon is of utmost importance. This critical review thoroughly summarizes the different types of daily used plastics, their types, properties, ways of accumulation and their effect on the environment and human health, treatment of waste materials, conversion of waste materials into carbon-based compounds through different synthetic schemes, and their utilization in energy storage devices particularly in supercapacitors, as well as future perspectives. The main purpose of this review is to help the targeted audience to design their futuristic study in this desired field by providing information about the work done in the past few years.

Non-invasive sampling of bats reflects their potential as ecological indicators of elemental exposure in a diamond mining area, northern Limpopo Province, South Africa

Bats have been proposed as reliable bioindicators for monitoring bioaccumulation of elements and chemicals in natural and transformed ecosystems. Non-invasive methods are becoming more popular as research moves away from destructive methodologies. We present the first concentrations of 23 elements in Mops condylurus and Tadarida aegyptiaca (Molossidae) fur and blood from an opencast diamond mine and reference area using inductively coupled plasma mass spectrometry (ICP-MS). Concentrations of B, K, Rb and Cd in the bats' fur were significantly higher in the mining footprint compared to the reference area (P < 0.05). Other elements such as Zn and Hg were significantly higher in the blood of bats from the mining footprint than the reference area (P < 0.05), whereas Mn was significantly higher in the blood of bats from the reference area than from the mining footprint (P < 0.05). Sixteen of the 22 elements above the limit of detection, with the exception of Ba, were significantly higher in the fur samples than in the blood due to elements being incorporated over time into the fur as it grows, whereas blood reveals short-term exposure to elements. Concentrations of most of the elements were reasonably low except Al, Fe and Zn. In general, the element concentrations particularly in the fur samples were comparable with other international studies reporting elemental fur concentrations from anthropogenically impacted and natural areas. Fur and blood have the potential to be viable indicators of environmental toxicity, but research is required on toxic thresholds and physiological and ecological unknowns around element concentrations in bat tissues and organs.

The Use of Intrinsic Markers for Studying the Migratory Movements of Bats

Mortality of migratory bat species at wind energy facilities is a well-documented phenomenon, and mitigation and management are partially constrained by the current limited knowledge of bat migratory movements. Analyses of biochemical signatures in bat tissues ("intrinsic markers") can provide information about the migratory origins of individual bats. Many tissue samples for intrinsic marker analysis may be collected from living and dead bats, including carcasses collected at wind energy facilities. In this paper, we review the full suite of available intrinsic marker analysis techniques that may be used to study bat migration, with the goal of summarizing the current literature and highlighting knowledge gaps and opportunities. We discuss applications of the stable isotopes of hydrogen, oxygen, nitrogen, carbon, sulfur; radiogenic strontium isotopes; trace elements and contaminants; and the combination of these markers with each other and with other extrinsic markers. We further discuss the tissue types that may be analyzed for each and provide a synthesis of the generalized workflow required to link bats to origins using intrinsic markers. While stable hydrogen isotope techniques have clearly been the leading approach to infer migratory bat movement patterns across the landscape, here we emphasize a variety of lesser used intrinsic markers (i.e., strontium, trace elements, contaminants) that may address new study areas or answer novel research questions.

Domestic cats as environmental lead sentinels in low-income populations: a One Health pilot study sampling the fur of animals presented to a high-volume spay/neuter clinic

Non-human animals serve as sentinels for numerous issues affecting humans, including exposure to toxic heavy metals like lead. Lead plays a role in perpetuating cycles of poverty in low-income communities due to the inequitable distributions of indoor health risks from lower-quality housing and outdoor health risks from industry and polluters, compounded by inequitable distributions of heath care and education. In this pilot study, we explore the potential for studying lead in low-income populations by partnering with nonprofit veterinary outreach programs. We investigate the lead concentration in fur samples of 85 domestic cats (Felis catus) presented to a high-volume spay/neuter clinic and report a mean of 0.723 μg of lead per gram of fur. This study reveals new information about lead exposure in cats in the USA, including that females had greater lead exposure than males, lead exposure increased with increasing amount of access to the outdoors, and lead exposure increased in cats with decreased body condition. We propose that pet, feral, and free-roaming cats presented to high-volume spay/neuter clinics could serve as a source of data about lead exposure in disadvantaged communities where these clinics already operate. Such a non-invasive surveillance system using inert, unobtrusively obtained samples could be deployed to detect highly exposed cats, prompting to follow up contact to a cat's caretakers to recommend seeking lead testing for themselves, their families, and their neighbors.

High concentrations of lead (Pb) in blood and milk of free-ranging brown bears (Ursus arctos) in Scandinavia

Exposure to lead (Pb) is a global health problem for both humans and wildlife. Despite a dramatic decline in human Pb exposure following restrictions of leaded gasoline and industry and thereby an overall reduction of Pb entering the environment, Pb exposure continues to be a problem for wildlife species. Literature on scavenging terrestrial mammals, including interactions between Pb exposure and life history, is however limited. We quantified Pb concentration in 153 blood samples from 110 free-ranging Scandinavian brown bears (Ursus arctos), 1-25 years old, using inductively coupled plasma sector field mass spectrometry. We used generalized linear models to test effects of age, body mass, reproduction status and spatial distribution on the blood Pb concentrations of 56 female bears. We sampled 28 females together with 56 dependent cubs and paired their blood Pb concentrations. From 20 lactating females, we measured the Pb concentration in milk. The mean blood Pb concentration was 96.6 μg/L (range: 38.7-220.5 μg/L). Both the mean and range are well above established threshold concentrations for developmental neurotoxicity (12 μg/L), increased systolic blood pressure (36 μg/L) and prevalence of kidney disease in humans (15 μg/L). Lactating females had higher Pb blood concentrations compared to younger, non-lactating females. Blood Pb concentrations of dependent cubs were correlated with their mother's blood Pb concentration, which in turn was correlated with the Pb concentration in the milk. Life-long Pb exposure in Scandinavian brown bears may have adverse effects both on individual and population levels. The high blood Pb concentrations found in brown bears contrast the general reduction in environmental Pb contamination over the past decades in Scandinavia and more research is needed to identify the sources and pathways of Pb exposure in the brown bears.

Nanoplastics as a Potential Environmental Health Factor: From Molecular Interaction to Altered Cellular Function and Human Diseases

The problem of plastic pollution is becoming increasingly important and has attracted great interest in the last few years. Polystyrene is one of the most used plastic types in the food and beverage industry, medical and laboratory devices. Increased plastic production and increased food, water, and air pollution and contact with nanoplastics may cause long-lasting changes and predispose to adverse developmental and degenerative diseases through mechanisms that are not yet understood.

The aim of this article is to provide an overview of current knowledge to plastics, especially polystyrene, and their impact on the human health. In particular, we discuss the major sources of plastic waste, polystyrene surface chemistry, as well as mechanisms by which plastics degrade in the environment. We also provide an insight into cellular uptake mechanism and the molecular interaction of polystyrene nanoparticles and human cells. This review offers scientists and clinicians useful information and could be used as a starting point for more in-depth analysis of nanoplastics as a potential environmental health factor.